This application claims priority from German Patent Application Nos. 102 42 390.3 and 103 29 835.5, which are incorporated herein by reference.
The invention relates to an apparatus at a draw frame or other textile machine having a drawing mechanism for the doubling and drafting of fibre slivers.
Certain forms of draw frame have a drawing mechanism frame for accommodating the drawing mechanism, which has at least two pairs of rollers each comprising an upper roller and a lower roller, and means for adjusting the spacing of at least one of the lower rollers in relation to another lower roller, in each case having a mounting device for accommodating the lower roller, and lower rollers are arranged to be driven by at least one drive element endlessly revolving around pulley wheels and wherein each lower roller has a roller-driving pulley wheel.
In a known apparatus (DE-OS 20 44 996), the mountings of the intake and middle lower rollers are displaceable on the frame of the machine so that the extent of the drawing zone can be matched to the particular fibre staple. A tensioning pulley wheel, which is displaceable in a guideway in the frame of the machine, allows the length of the toothed belt to be modified in accordance with the changed spacing between the axes of the middle roller and a guide pulley wheel, brought about by displacement of the intake roller. The middle roller is driven by a further toothed belt. The latter toothed belt is tensioned by a tensioning pulley wheel which is fastened to the machine frame and which can pivot about one axis; as a result, it can also be matched to changed spacings between the axes of the intake roller and middle roller. It is disadvantageous that displacing devices for displacement of the intake roller and the middle roller and additional tensioning devices for re-tensioning of the toothed belts after the displacement operations are necessary, requiring a considerable outlay in terms of construction. In addition, it is disadvantageous that a number of work steps are required for the displacement operations and the subsequent re-tensioning operations. The belt tension is destroyed by the displacement process. Where the displacement is carried out manually, spacers are inserted between the mountings, the mountings being pushed against the spacers so that, in this case too, the amount of set-up work is considerable. Finally, the displacement and re-tensioning operations result in a doubling of potential error sources when setting the spacings and belt tensions.
It is an aim of the invention accordingly to provide an apparatus of the kind described at the beginning that avoids or mitigates the disadvantages mentioned and that especially is of simple construction and allows a considerable reduction in the work and time required for adjustment of the slider(s) and, accordingly, of the extent(s) of the drawing zone(s), without re-tensioning the drive belt after the adjustment.
The invention provides a drawing mechanism having a drawing mechanism frame, at least two pairs of rollers each comprising an upper roller and a lower roller and having a mounting device for accommodating the lower roller, means for adjusting the spacing of at least one of the lower rollers in relation to another lower roller, and at least one drive device comprising a drive element endlessly revolving around pulley wheels, wherein said pulley wheels comprise a guide pulley wheel provided on a said mounting device and a roller-driving pulley wheel for driving the lower roller accommodated by that mounting device, said roller-driving pulley wheel and said guide pulley wheel acting one after another on opposed sides of the drive element.
The measures according to the invention make it possible, by simple means, for the mountings and, as a result, the extents of the drawing zones (nip line spacings) to be adjusted in a short time. For the purpose of adjusting the extents of the drawing zones, elegant use is made of existing structural elements necessarily present in the drawing mechanism, namely a roller-driving pulley wheel and the drive belt. Separate apparatuses for adjustment are not required. As a result of the fact that the drive belt is in tension before, during and after adjustment, further apparatuses for re-tensioning the drive belt after the adjustment are not required, which allows the extents of the drawing zones of the drawing mechanism to be changed in a short time by means that are especially simple in terms of construction.
Advantageously, the drive device can be used for adjusting the position of the mounting device of said lower roller, whereby said adjustment of said spacing is effected. Advantageously, at least one pulley wheel and the tensioned drive element are used for adjusting the mounting device. Advantageously, the drive element is stationary and the pulley wheel is rotated. Advantageously, the pulley wheel is stationary and the drive element is moved. Advantageously, the rotation of the pulley wheel or the movement of the drive element is converted into the adjusting movement of the slider. Advantageously, at least one guide pulley wheel is attached to each slider (mounting); and the roller-driving pulley wheel or guide pulley wheel(s) act, in each case one after the other, on both sides of the tensioned drive element. Advantageously, the rotation of the pulley wheel or the movement of the drive element is accomplished manually. Advantageously, the slider is linearly displaceable.
Advantageously, the drive element is a toothed belt. Advantageously, an endless flexible toothed belt is present. Advantageously, the pulley wheels comprise toothed belt wheels. Advantageously, the pulley wheels comprise guide pulley wheels. Advantageously, at least one driving pulley wheel is provided. Advantageously, driven pulley wheels are present. Advantageously, the drive element loops around the pulley wheels. Advantageously, the drive element and the pulley wheel are in engagement with one another. Advantageously, the pulley wheel for adjustment of a slider is the drive pulley wheel of a lower roller (roller-driving pulley wheel). Advantageously, the slider is displaceable during adjustment. Advantageously, the slider is arranged to be stopped. Advantageously, the stopping arrangement is releasable. Advantageously, a display device for the position of the slider is present.
Advantageously, a drive motor is used for rotation of the pulley wheel. Advantageously, a drive motor is used for movement of the drive element. Advantageously, the drive motor is used for the lower rollers. Advantageously, a separate drive motor is used. Advantageously, belt shortening or belt lengthening is arranged to be automatically evened out during adjustment. Advantageously, the evening-out of belt length is carried out at a slider by two guide pulley wheels.
Advantageously, the lower rollers are arranged to be adjusted singly and independently of one another. Preferably, a roller-driving pulley wheel and a guide pulley wheel are attached to the slider of the intake roller and a roller-driving pulley wheel and a guide pulley wheel are attached to the slider of the middle roller. Advantageously, the drive element runs around the pulley wheels at the slider of the intake roller and around the pulley wheels at the slider of the middle roller in a mirror-reflected arrangement. Advantageously, the drive element is in tension before, during and after the displacement. Advantageously, the drive motor is in communication with an electronic control and regulation device. Advantageously, a measuring element is connected to the control and regulation device. Advantageously, the measuring element is capable of registering fibre-related and/or machinery-related measurement variables. Advantageously, adjustment of the slider is carried out when the drawing mechanism is in operation. Advantageously, adjustment of the slider is carried out when the drawing mechanism is not in operation. Advantageously, adjustment of the slider is carried out during can-changing. Advantageously, the draw frame is self-adjusting. Advantageously, adjustment of the slider is carried out by inputting adjustment variables. Advantageously, the adjustment variables can be input manually. Advantageously, a memory for adjustment variables is connected to the control and regulation device. Advantageously, the slider for the intake roller and the slider for the middle roller are arranged to be connected by a rigid connecting element. Advantageously, the connecting element is releasably connected. The spacing of the pairs of rollers in relation to one another may be adjustable without fibre material. The spacing of the pairs of rollers in relation to one another may be adjustable with fibre material. Advantageously, the extent of the preliminary draft zone can be adjusted. Advantageously, the extent of the main draft zone can be adjusted. Advantageously, the extent of the preliminary draft zone and the extent of the main draft zone can be adjusted. Advantageously, each lower roller has its own associated drive motor. Advantageously, the intake and middle lower rollers are arranged to be driven by one drive motor. Advantageously, a brake, stopping arrangement or the like is associated with the stationary pulley wheel. The brake, stopping arrangement or the like may be mechanical, electrical or electromagnetic. Advantageously, the drive motor is a self-braking motor. Advantageously, the drive motor drives a further drive train, which has a free-wheel arrangement or the like.
Advantageously, the mounting device consists of the mounting and the slider. The mounting and the slider may be fastened to one another, for example by bolts. The mounting and the slider may be of integral construction.
The invention also provides an apparatus at a draw frame having a drawing mechanism for the doubling and drafting of fibre slivers, having a drawing mechanism frame for accommodating the drawing mechanism, which has at least two pairs of rollers each comprising an upper roller and a lower roller, having means for adjusting the spacing of at least one of the lower rollers in relation to another lower roller, in each case having a mounting device for accommodating the lower roller, wherein lower rollers are arranged to be driven by at least one drive element endlessly revolving around pulley wheels, characterised in that at least one guide pulley wheel is attached to each mounting device; and the roller-driving pulley wheel or guide pulley wheel act, in each case one after the other, on both sides of the tensioned drive element.
Moreover, the invention provides a draw frame comprising a drawing mechanism as defined above.